Various vehicular sliding door structures of the type concerned are known and used heretofore. According to one such known vehicular sliding door structure disclosed in Japanese Patent Laid-Open Publication (JP-A) No. 2000-199375, a sliding door can be electrically driven, and an anti-pinch sensor is provided on a front end surface of the sliding door for detecting an object in a potential pinch region between the sliding door and a mating portion of the vehicle body. The anti-pinch sensor is comprised of a touch sensor fitted on a longitudinal edge of one arm of an L-shaped support bracket attached to the front end surface of the sliding door and extending between an upper end and a lower end of the front end face of the sliding door. The front end surface of the sliding door has an opening formed therein so that a sensor harness of the anti-pinch sensor can be introduced into an internal space of the sliding door for electrical connection with a sliding door control unit.
The opening formed in the front end surface of the sliding door is not closed and may allow dust to enter the internal space of the sliding door, which might deteriorate the performance of the sliding door control unit disposed inside the sliding door. The conventional sliding door structure further includes a protecting cover attached to a lower end portion of the support bracket so as to cover an end portion of the sensor harness. The protecting cover, which is provided separately from the support bracket, is disadvantageous as it increases the production cost of the sliding door structure and deteriorates the appearance of the sliding door structure.